This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The global goal of this project is to develop strategies for automatic morphology analysis in the rat embryo. The specimens will be harvested from pregnant Sprague Dawley rats. They will be then fixed accordingly to the staining method used in the previous study. Depending on the size of the specimen, the fixation will be achieved by immersion in a Bouins/Prohance solution at 20/1 for 5 min, 10 min, 20 min, 30 min, 1 hr, 1.5 hrs, and 3.5 hrs for respectively 12-day, 13-day, 14-day, 15-day, 16-day, 17-day, and 18-day fetuses. The scanning method will include the use of an appropriate coil adapted to the size of the embryo to fit as well as possible. 3D images will be acquired using different sequences: T1-weighted, T2-weighted, and diffusion-weighted, at high signal-to-noise ratios. A combination of these different weighted images will be used to develop an automated segmentation of the rat embryo.